1. Field of the Invention
The present invention relates to a steering wheel for a vehicle and more particularly to a steering wheel which can be heated and can be made comparatively inexpensively.
2. Description of Related Art
In cold weather, the steering wheel of a vehicle feels very cold to the hands of the operator and a heated steering wheel greatly improves the comfort of the operator which contributes to the safe operation of the vehicle.
This problem has been reorganized and U.S. Pat. No. 4,547,655 to Kurata et al is directed to an electrically heated steering wheel. The object of the patent is to obtain uniform warming in a relatively short time and to avoid a zone of high temperature at the terminals. A metal vaporization technique is used to deposit a metal film on the rim. An electrically insulating sheet covers the metal film and an electric heat generating member covers the insulating sheet. An outermost electrically insulting cover made of woven fabric is in contact with the hands of the vehicle operator.
In U.S. Pat. No. 6,365,875 to Kreuzer et al, heating wires are disposed on a wheel rim and are covered by a casing. The casing is a support layer having good thermal conductivity which is covered with a veneer wood.
Zhao et al in U.S. Pat. No. 6,392,195 disclose a woven fabric made from nylon coated with silver. A foam layer covers the heating element and a leather wrap or wood shell encases the foam.
In U.S. Pat. No. 6,441,344 to Bonn et al, a layer of electrically conducting plastic surrounds the core of the rim. A pair of electrodes extend the length of the conductive layer. An outer casing is made of leather, wood or film.
All of the known heated steering wheels are costly to prepare and, as a result, heated steering wheels are presently available only in the more luxurious upgraded vehicles.
This is a need for a heated steering wheel which can be made relatively in expensively so the option of a heated steering wheel can be made available to mid or low end vehicles regardless of the make or model.
It is an object of the present invention to provide a method of making a heated steering wheel at relatively low cost so the heated steering wheel can be available in mid to low end vehicles.
It is a further object of the present invention to provide a steering wheel which can be heated in cold weather to improve the comfort of the operator and improve safety of operating the vehicle.
In accordance with the teachings of the present invention, there is disclosed a method of forming a heated steering wheel for a vehicle. A sheet of moldable plastic is provided. The sheet has a first face and an opposite second face. A pattern is silk screened on the second face of the sheet using an electrically conductive ink. The pattern has two opposite ends. The sheet is vacuum formed into a desired shape. Two electrical leads are provided. Each lead is electrically connected to a different one of the ends of the silk screen pattern. A plastic resin is molded adjacent to the second face of the plastic sheet wherein the silk screen pattern and the electrical leads are encapsulated and the formed plastic sheet is reinforced. The reinforced plastic sheet is attached to the steering wheel with the silk screen pattern oriented toward the steering wheel.
In further accordance with the teachings of the present invention, there is disclosed a heated steering wheel having a center core. A molded sheet of plastic has a first outer face and a second inner face. A pattern of electrically conductive ink is formed on the second inner face. A pair of electrical leads are connected to the pattern of electrical conductive ink. A molded plastic resin is formed in the inner second face, the molded plastic resin encapsulating the pattern of electrically conductive ink and the pair of electric leads. The molded plastic resin is connected to the center core.